auto-bind-inheritance's Introduction

auto-bind-inheritance

Automatically bind methods to their class instance and works on parent methods.

This package was created directly as a result of failing on extended classes in the auto-bind package.

There are issues with getters which are initialized in the constructor:

initialize the getter/setter inside the getter/setter (not ideal)
call autoBindI at end of final child (not ideal)
manually call autoBindI
avoid getter/setters

Install

$ npm install --save auto-bind-inheritance

Usage

// const autoBind = require('auto-bind'); // drop-in replacement
const autoBindI = require('auto-bind-inheritance');

class A {
	constructor() {
		this.val = 'A';
		autoBindI(this);
	}
	method2() { console.log('A.method2 ', this.val); }
}
  
class B extends A {
	constructor() {
		super();
		this.val = 'B';
	}
	method1() { console.log('B.method1 ', this.val); }
}


let a = new A();
let b = new B();


b.method1();
b.method2();
let mb1 = b.method1;
let mb2 = b.method2;
console.log(mb1.name);
console.log(mb2.name);
mb1();
mb2();


// With `autoBind(this)`, the above could have resulted in:
//=> 'B.method1  B'
//=> 'A.method2  B'
//=> 'bound bound method1'
//=> 'method2'
//=> 'B.method1  B'
//=> 'exception "Cannot read property 'val' of undefined"'

// With `autoBindI(this)`, the above now correctly results in bound and callable methods:
//=> 'B.method1  B'
//=> 'A.method2  B'
//=> 'bound method1'
//=> 'bound method2'
//=> 'B.method1  B'
//=> 'A.method2  B'

API

autoBind(self)

Bind methods in self to their class instance. Returns the self object. Can be placed in the parent and will be call on all child classes because the prototype chain has already been created.

self

Type: Object

Object with methods to bind.

auto-bind - Automatically bind methods to their class instance

License

MIT © Chad Wingrave

auto-bind-inheritance's People

Contributors

Stargazers

Watchers

auto-bind-inheritance's Issues

Bug with getter and setter methods

The code is executing the getter method but the class is not yet initialized.

const autoBindI = require('auto-bind-inheritance');

class A {
   constructor() {
       autoBindI(this);
   }
}

class B extends A {
    constructor() {
         super();
         this.foo = [];
    }

    // when `autoBindI` detects this method, this.foo is still undefined
    // `self[key] = val.bind(self);` will now result in
    // "Cannot read property '0' of undefined"
    get bar() {
        return this.foo[0];
    }
}

new B();